Appendix S1: PRISMA Checklist

Appendix S1: PRISMA Checklist Section/topic # Checklist item Reported on page # TITLE Title 1 Identify the report as a systematic review, meta-analysis, or both. 1 ABSTRACT Structured summary 2 Provide a structured summary including, as applicable: background; objectives; data sources; study eligibility 2-3 criteria, participants, and interventions; study appraisal and synthesis methods; results; limitations; conclusions and implications of key findings; systematic review registration number. INTRODUCTION Rationale 3 Describe the rationale for the review in the context of what is already known. 4 Objectives 4 Provide an explicit statement of questions being addressed with reference to participants, interventions, 4+Methods Section comparisons, outcomes, and study design (PICOS). (5-12) METHODS Protocol and 5 Indicate if a review protocol exists, if and where it can be accessed (e.g., Web address), and, if available, provide 5 registration registration information including registration number. Eligibility criteria 6 Specify study characteristics (e.g., PICOS, length of follow-up) and report characteristics (e.g., years considered, 6 language, publication status) used as criteria for eligibility, giving rationale. Information sources 7 Describe all information sources (e.g., databases with dates of coverage, contact with study authors to identify 7 additional studies) in the search and date last searched. Search 8 Present full electronic search strategy for at least one database, including any limits used, such that it could be Online material 1 repeated. [ON1] Study selection 9 State the process for selecting studies (i.e., screening, eligibility, included in systematic review, and, if applicable, 7, 11-12 included in the meta-analysis). Data collection 10 Describe method of data extraction from reports (e.g., piloted forms, independently, in duplicate) and any processes 8-9 process for obtaining and confirming data from investigators. Data items 11 List and define all variables for which data were sought (e.g., PICOS, funding sources) and any assumptions and 8 simplifications made. Risk of bias in 12 Describe methods used for assessing risk of bias of individual studies (including specification of whether this was 9 individual studies done at the study or outcome level), and how this information is to be used in any data synthesis. Summary measures 13 State the principal summary measures (e.g., risk ratio, difference in means). 12 Synthesis of results 14 Describe the methods of handling data and combining results of studies, if done, including measures of consistency 11 (e.g., I2) for each meta-analysis. Section/topic # Checklist item Reported on page # Risk of bias across 15 Specify any assessment of risk of bias that may affect the cumulative evidence (e.g., publication bias, 13, 14, 17, 32 studies selective reporting within studies). Additional analyses 16 Describe methods of additional analyses (e.g., sensitivity or subgroup analyses, meta-regression), if done, Meta-regressions (10-11) indicating which were pre-specified. RESULTS Study selection 17 Give numbers of studies screened, assessed for eligibility, and included in the review, with reasons for 12 & Figure 1 exclusions at each stage, ideally with a flow diagram. Study characteristics 18 For each study, present characteristics for which data were extracted (e.g., study size, PICOS, follow-up Table 1 period) and provide the citations. Risk of bias within 19 Present data on risk of bias of each study and, if available, any outcome level assessment (see item 12). Table 1 & ON2 studies Results of individual 20 For all outcomes considered (benefits or harms), present, for each study: (a) simple summary data for Table 1, Figures 2 & 3 studies each intervention group (b) effect estimates and confidence intervals, ideally with a forest plot. Synthesis of results 21 Present results of each meta-analysis done, including confidence intervals and measures of consistency. 12-23 Risk of bias across 22 Present results of any assessment of risk of bias across studies (see Item 15). 12-23 studies Additional analysis 23 Give results of additional analyses, if done (e.g., sensitivity or subgroup analyses, meta-regression [see 12-23 Item 16]). DISCUSSION Summary of evidence 24 Summarize the main findings including the strength of evidence for each main outcome; consider their 23-25 relevance to key groups (e.g., healthcare providers, users, and policy makers). Limitations 25 Discuss limitations at study and outcome level (e.g., risk of bias), and at review-level (e.g., incomplete 31-34 retrieval of identified research, reporting bias). Conclusions 26 Provide a general interpretation of the results in the context of other evidence, and implications for 25-30 future research. FUNDING Funding 27 Describe sources of funding for the systematic review and other support (e.g., supply of data); role of 35 funders for the systematic review. From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med 6(6): e1000097. doi:10.1371/journal.pmed1000097. For more information, visit: www.prisma-statement.org.